Swedish telecoms equipment maker Ericsson said on Tuesday it had sued Indian handset maker Micromax and its distributor for infringement of wireless patent rights.

Ericsson (Stockholm, Sweden) was confirming an earlier report in the Economic Times of India that it had sued after Micromax (Gurgaon, India) refused to sign license agreements for several wireless technologies.

"It is once again about FRAND (fair, reasonable and non-discriminatory terms)," Ericsson spokeswoman Karin Hallstan said. She declined to comment further.

Ericsson's 30,000-plus patent portfolio covers much of the technology that enables both mobile phones and the networks that support them to work.

Rivals hold other so-called essential standard patents and the industry has agreed a system of licensing on fair, reasonable and non-discriminatory terms (FRAND) to ensure no one can block the development of mobile communications.

Micromax said in a statement it was "committed to negotiating a FRAND license with Ericsson as has Ericsson undertaken to providing a Fair, Reasonable and Non-discriminatory license to Micromax."

It declined further comment.

Ericsson has been getting tough over patents recently.

Last year, it sued Samsung (Seoul, South Korea) for allegedly failing to sign license agreements on reasonable grounds to use its technology.

Samsung, which is embroiled in a legal war with Apple (Cupertino, CA, USA) in more than 20 disputes in 10 countries, filed a counter-claim earlier this month.

In a recent interview with Reuters, Ericsson's chief intellectual property officer, Kasim Alfalahi, said the company was not out to squeeze the last dollar out of rivals who use its technology.

However, he warned that Ericsson would protect its rights.

"There are players who think they can get a free ride; use Ericsson technology without paying," Alfalahi said.

"They know very well that we will enforce our patents."

On its website, Micromax says it is the 12th largest handset manufacturer in the world, selling in total around 1.3 million handsets a month in Asia, the Middle East and Brazil.

Ericsson no longer has a handset business after partner Sony (Tokyo, Japan) bought it out of Sony Ericsson in 2011.

It had patent revenues of 6.6 billion crowns in 2012, up from 6.2 billion the previous year and 4.6 billion in 2010. Total revenues for the whole of Ericsson's business topped 225 billion crowns last year.

(Reporting by Simon Johnson, additional reporting by Aravindan Ardhana in Delhi; Editing by David Cowell)